Abstract 2973: Adhesion of tumor cells to ECM microarrays identifies novel ECM interactions in metastasis

Abstract

Abstract Extracellular Matrix (ECM) interactions play an essential role in all phases of tumorigenesis and metastasis. Here, we report a novel ECM microarray platform for investigating the combinatorial effects of ECM adhesion on cancer metastasis. This platform is composed of micropatterned spots of nearly 800 unique ECM combinations, and can be used to measure cellular adhesion, proliferation, marker expression, or any other phenotypic responses that can be queried by microscopy. Using a genetic model of lung adenocarcinoma (KrasLSL-G12D/+;p53flox/flox), we tested the adhesion of cell lines derived from tumors throughout the stages of tumor progression. We found that the adhesion profiles of primary tumors and their metastases could be distinguished by Euclidian clustering whereas gene expression profiles of the same cells could not. In particular, we identified combinations of ECM molecules that exhibited preferential adhesion to either the metastatic or primary tumor cell lines. Histological examination of tissues from mice bearing the autochthonous tumors confirmed that the primary tumor-associated molecules are present in the lungs but not the sites of metastases. Conversely, metastasis-associated ECM molecules were not present in the primary tumors, but were expressed at the metastatic sites. From the known integrin-ECM interactions, we then identified several integrins as playing a functional role in ECM interactions during lung cancer metastasis. Flow cytometry confirmed higher expression of these candidates on the cell surface of the metastatic lines than the primary lines. Knockdown of integrin expression in the metastatic cells by shRNAs reduced the adhesion of the cells to the cognate ECM molecules in vitro, confirming a functional role in our phenotypic assay. Additionally, abrogation of cell-ECM interactions through inhibition of contact between the metastasis-associated molecules and the receptors on the metastatic cells prevented metastases from seeding in vivo. Thus, ECM microarrays offer a novel platform for the phenotypic characterization of tumor cells from different stages of tumor progression, identification of key ECM interactions, and the identification of potential therapeutic targets in cancer metastasis. In the future, we will apply the ECM Microarrays for the stratification of patients to assist in diagnostics and treatment guidance. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2973. doi:1538-7445.AM2012-2973